Process Planning Method Of Additive-subtractive Hybrid Manufacturing For Complex Structural Parts

Additive-subtractive hybrid manufacturing offers a new solution for manufacturing complex structural parts.The process planning of hybrid manufacturing directly affects the part quality as well as the productivity.During the hybrid manufacturing process,the geometric profile of the in-process part is dynamically growing,the tool accessibility of the following operations is hard to predict and thus greatly increase the intractability of the process planning.In order to solve the above problem,a process planning method of hybrid manufacturing for complex structural parts is studied in this thesis.The main work is as follows:(1)Towards the problem of multi-axis slicing in hybrid manufacturing for complex structural parts,a centroid-axis-based multi-axis slicing method is proposed.First,the concept of "columnar" feature is defined by which the parts can be divided into multiple "columnar" features.Meanwhile,the "centroid axis" of every "columnar" feature is extracted.Finally,by constructing corresponding slicing constraints,a multi-axis slicing algorithm is devised in a iterative manner,which lays a foundation for the process planning.(2)Aiming at the problem of hybrid manufacturing sequence planning for complex structural parts caused by the dynamic growing of the in-process part geometric state,a top-down sequence planning method is studied.Tool accessibility is evaluated based on Guassian spherical mapping,while an analytical model for sequence planning is constructed accordingly.By using a top-down strategy to check the state of the tool accessibility,the problem of interference uncertainty becomes definite and can be solved.The optimization of part decomposition scheme and manufacturing sequence is eventually realized.(3)Targeting at the problem of path generation for hybrid manufacturing,both the path generation methods for additive and subtractive processes are studied.For additive process,a printing path generation method is developed for the objective of accuracy and efficiency.For subtractive process,a toolpath generation method is presented by taking the motion stability into consideration.(4)Based on the above studies,the corresponding hybrid manufacturing process planning system is developed and verified by simulation and physical experiments.